Combination offset and straight internal bore gauge



Jan. 8, 1952 A. EISELE COMBINATION OFFSET AND STRAIGHT INTERNAL BOR.' GAU Filed Aug. 2l, 194'? Patented Jan. 8, 1952 OFFICE COlWBINATION OFFSET AND STRAIGHT INTERNAL BORE GAUGE Andrew Eisele, Detroit, Mich.

Application August 21, 1947, Serial No. 769,885

This invention relates to gauges and in particular to internal bore gauges.

One object of this invention is to provide a combination off-set and straight internal bore gauge which may be quickly converted from one type to the other merely by adding or removing a quickly-detachable elbow tting or adapter between the measuring head and the gauge body which carries the dial indicator.

Another object is to provide an improved mechanism for transmitting motion from the measuring head to the dial indicator of an internal bore gauge, this improved mechanism minimizing mechanical errors.

Another object is to provide a combination oiset and straight internal bore gauge having a tubular body carrying a dial indicator at one end and an elbow at the other end with a measuring head on the elbow such that any one or all of the head, elbow and dial indicator may be turned completely around or adjusted to any desired angle, thereby adapting the gauge to the measurement of bores in almost inaccessible locations.

Another object is to provide a combination offset and straight internal bore gauge as set forth in the preceding objects, wherein the motion- `transmitting mechanism is such that the axisv `of the measuring head may be placed or constructed at any angle relatively to the axis of .the tubular gauge body carrying the dial indicameasuring head taken along the line 4-4 in Figure l;` and Figure 5 is a fragmentary central vertical section through the gauge shown in Figure 1 with the elbow attachment or adapter removed and the measuring head mounted directly upon the tubular gauge body for straight measurements.

Referring to the drawings generally, Figures 1 and 5 show a preferred form of the combination odset and straight internal bore gauge, generally :designated I0, according to a preferred form of 1 Claim. (Cl. 33-178) the invention. The gauge Ill consists generally of a dial indicator II mounted on one end of a tubular body I2, the opposite end of which y plained below.

Referring to the drawings in detail, the dial indicator II, shown in side elevation in Figure 1, is of a conventional type whose details form no part of the present invention. The dial indicator II consists of a hollow stem I5 having a bore IB in which a plunger I I is reciprocable. One end of the plunger I'I carries an enlargement I8 with a rounded contact portion I9. The other end of the plunger (not shown) enters the cylindrical dial indicator casing 20 and transmits its motion through conventional multiplying mechanism (not shown) to a shaft 2| carrying a pointer or needle 22. A rotatable dial 23 with graduations 24 indicates the travel of the plunger I1 in some accepted standard of measurement, such as thousandths of an inch, the dial 23 being rotatable manually in order to set the needle 22 to read upon zero.

The gauge body I2 is of tubular form and at its upper end is provided with a cylindrical socket 25 into which ts the stem I5 of the dial indicator II. The latter is clamped in position by means of a set screw`26 passing through a bore 21 into a co-axial threaded bore 28 formed respectively in ears 29 and 30 (Figure 2) projecting laterally from the upper. end of the gauge body I2 and separated from one another by a radial slot 3| extending inward into the socket 25.

The socket 25 is formed in the enlarged upper end 32 of the gauge body I2, and terminates in an annular shoulder 33 (Figure 1) where it joins the reduced diameter portion 34 of the gauge body I2. Mounted on the upper part of the reduced diameter body portion 34 in abutment with the annular shoulder 33 is the hub 35 of` a handle 36, the hub 35 being bored as at 31 for the passage of the gauge body portion 34. A set screw 38 threaded in a transverse bore 39 leading into the bore 3I secures the handle 36 in position.

Immediately below the socket 25 the gauge body l2 is provided with a threaded bore 40 f Figure 1) which in turn opens into an unthreaded bore 4I, the latter at its lower end opening into a reduced diameter smooth bore 42.

Reciprocably mounted inthe bore 42 is a motiontransmitting rod 43 having an enlarged head 44 located within the bore 4I. The rod 43 at its upper end 45 engages the rounded end I9 on the enlargement IS of the dial indicator plunger I'I and transmits its'motion thereto. Surrounding the upper portion of the rod 43 within the bore 4| is a spiral compression spring 46, one end of which engages the enlarged head 44 and urges itv downward while the other end engagesy a collar 4l threaded into the threaded bore 40 and having a central hole 48 for the passage of the rod 43. Y

The lower end of the bore 42 opens into an enlarged socket or counterbore 49 (Figure 1), the side wall thereof being provided with a threaded hole U containing a -set screw 5 I. Mounted in the counterbcre 49 is the upper end of a tubular stem 52 having a bore 53 through which the' lower end of the motion-transmitting rod 43 passes. The lower end of the stem 52 is secured -in the vertical bore v54V of' the velbow attachment or' adapter .I3 by means of a set screw 55 threaded into a hole 56 andv engaging a flat portion 51 .formed in the stem 52 to prevent rotation thereof.

the Vrod 43 engages the sector edge 6|V whereas the sector vedge B2 at its point engages the rear- 'ward end 66 of the reduced diameter portion 6-1 of the elbow motion-transmitting rod B8.

The rodportion 3l passes through a hole 69 in the 4side wall of the bore 54 and enters the hori- `'zontal elbow bore Iii in the horizontal arm 54.

The bore it receives a cup-shaped sleeve II (Figure 1) which is provided with an internal bore f T2 in which the rod B8 is reciprocably mounted. fA set vscrew 'I3 threaded into a transverse hole '|14 locks the sleeve 'II in any desired position. Mounted on the reduced diameter rod .portion 6l Yis a compression coil spring 1,5, one 'end of which engages the surface around the hole 59 whereas Vthe other end engages lthe annular shoulder 'I6 between the reduced diameter portion 6l' and the main portion Il of the rod 58. The opposite end 'of the rod B8 is provided with 'a reduced diameg'terportion I8 (Figure 1) having a contact end Y'19. Y The *reduced diameter portionn'l passes through a hole B5 in the end wall 8l of the cupped sleeve .'II, the latter being provided with a at spot 82 engaged by a set screw B3 threaded through a hole 84 in the tubular shank 85 of the measuring head I4' to clamp the sleeve 'H in position and prevent its rotation.

' Projecting from the outer end wall 8| of the sleeve 'II is a pair of approximately semi-cylindrical spaced arms 85 (Figures 3 and 4), the for- Ward ends` of which are tapered and boredto receive a pivot pin 5l uponwhich vvismounted a motion-transmitting sector 88. The sector 83 is lprovided with Contact edges 89 and 90 similar to the. contact edges 6| and 52 kof the sector 69 and arranged at a similar angle to one another. 'Ihe edge 89 is engaged by the end 'I9 of the rod 58 (Figures 1 and 4).

The tubular shank 35 is provi-ded with a bore 9| sco-extensive with the bore 'I9 (Figure 1) and similarly receiving the sleeve |I. The reduced diameter portion I8 of the rod 68 passes through a hole 92 in the end wall 93 of the shank 85, which serves as an abutment for the end wall 8| of the sleeve'II. The head I4 is approximately in the form of a partial sphere and contains a cylindrical cavity 94 which is closed at its upper end by a disc 35 having a central bore 96 into which a threaded xed 'contact pin'91 is screwed and locked in position by a lock nut 93 (Figure 1).

The head i4 is provided with a central bore '99 (Figure 3) and a pair of parallel outer bores |00. Reciprocably mounted in the central bore 99 is a reciprocable measuring pin I0| having a rounded end |92 and a longitudinal flat spot |93 engaged by the inner end of a set screw |04 (Figure l1) threaded into the bore |55 to prevent rotation of the measuring pin IGI. The upper end |03 of the measuring pin Il engages thecorner or point of the contact edge 9i) of the sector 88.

Reciprocably mounted in they bores |99 is a pair of locating pins |91 (Figure 3), the lower ends of which are rounded as at |93. The upper ends of the locating pins I9? are interconnected by an arcuate bridge member I 59 secured thereto (Figure 4). Coil springs H9 seated at their upper ends in sockets iI (Figure 3) in the disc V"95 and at their lower ends engaging the bridge member |09 urge the latter and its locating pins '|81 outward through the bores |90.

' In the operation of the invention, let it be Yfirst assumed that the internal bore gauge is to 'be Vemployed in its offset form vshownV in Figure 1, with the elbow attachment or adapter I3 in the position 'shown therein. The operator grasps the handle 36 and, having setV the dial graduations 24 at zero relatively to the needle 2|, inserts the measuring head I4 into the bore to be'measured. The measuring pin is urged downward by `the coil spring 15, rod 38 and seetor 8S, until' its rounded end |42 engages the internal bore I I2 to be measured (Figure 3), the fixed pin '91' and the locating pins |91 cooperating to cause the axis of the pins 91 and IUI to lie accurately along a cross diametersof the bore II2. The motion of the pinY |0| is transmitted through the sectors 88 and 59 and the rods 68 and 43 to the dialv indicator plunger I'I and is registered upon the graduations 24. Vof

the dial 23. Y

In order to reach ordinarily inaccessible positions, the head. I4 may be rotated relatively to the elbow attachment Vor adapter I3 by loosening the ,s et screw 'I3 and tightening it again when the desired. turning of the head I4 around its shank has been accomplished. Similarly, the arm |53 of the elbow attachment or adapter I3 may also be rotated relatively to the tubular gauge body I2 by loosening the set screw 5| and retightening it when the desired position has been reached. The dial indicator II may also be rotated so that its dial 23 is visible most conveniently by loosening the set screw 25 and retightening it when the desired position has been reached.

To convert the gauge I0 to the straight form shown in Figure 5, the operator unscrews the set screws l55 and 83 (Figure 1) so that their ends are at least ilush with the bores 54 and 9! respectively. The head |4 may then be withdrawn from its telescoping engagement with the sleeve 'I I, and in the same manner, the elbow adapter or attachment I3 may be withdrawn from engagement with the tubular stem 53. The elbow adapter or attachment I3 is then stored in any convenient place, such as the case of the instrument, and the tubular shank 85 of the head I4 is mounted in telescoping relationship upon the lower end of the stem 52, replacing the tubular arm 63 of the elbow adapter or attachment I3. The parts now occupy the positions shown in Figure 5, and the set screw B3 may now be tightened against the flat spot 51 of the stem 52 in order to lock the head I4 in position.

The head I4 in the straight arrangement of the gauge I shown in Figure 5 may also be rotated relatively to the body portion I2 by loosening the set screw 5I. The latter is retightened when the head I4 has been rotated to the desired position. The dial indicator II may also be rotated relatively to the body I2 by loosening the set screw 26 in the manner described above.

The present invention, therefore, provides an internal bore gauge which is quickly convertible from an olset gauge to a straight gauge and vice versa. The motion-transmitting mechanism is simple yet effective, and reduces errors to a minimum. The dial indicator and the measuring head may be turned relatively to the gauge body, and these may further be turned relatively to the elbow adapter or attachment if it is being used at the moment. In this manner, the gauge is adapted to the measurement of bores which are otherwise inaccessible, and the graduations can be easily read by placing the dial of the dial indicator in the most convenient position. If desired, an elbow adapter having an acute angle or an obtuse angle between the arms may be employed in place of the right angle form I3 shown in Figure 1. Different lengths of interchangeable fixed contact pins 91 are provided in order to permit the most eflicient measurement of different ranges of bore diameters.

What I claim is:

A combination straight and offset internal bore gauge comprising an elongated body structure, a dial indicator mounted thereon, an elbow structure removably mounted on said body structure, a measuring head structure removably mounted on said elbow structure, a xed measuring pin and a movable measuring pin mounted in said head structure, and motion-transmitting mechanism mounted on and extending through said structures, said mechanism operatively interconnecting said dial indicator and said movable measuring pin, said mechanism including an elongated reciprocable motion-transmitting rod mounted in said body structure and operatively connected to said dial indicator, and a sector-shaped motion-transmitting member pivotally mounted on one of said structures and having contact edges disposed at an obtuse angle relatively to one another, one of said contact edges engaging said movable measuring pin and the other contact edge engaging said rod, said body structure and said head structure having mating stem and socket portions thereon and said elbow structure having stem and socket portions thereon mating with the stem and socket portions of said body and head structures, whereby said measuring head structure is interchangeably mountable on said body structure in place of said elbow structure.

ANDREW EISELE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,804,383 Litterio May 5, 1931 2,268,579 Eisele Jan. 6, 1942 2,333,128 Robins Nov. 9, 1943 2,419,433 Aller Apr. 22, 1947 FOREIGN PATENTS Number Country Date 190,458 Switzerland Apr. 30, 1937 92,613 Sweden June 21, 1938 541,129 Great Britain Nov. 18, 1941 

